Tag Archives: Fruits

The largest benefits were seen in people who ate seven or more servings of fruits and vegetables a day compared with those who ate less than one serving, with the higher level of consumption associated with significantly lower all-cause mortality (hazard ratio 0.67; 95% CI 0.58-0.78), lead researcher Oyinlola Oyebode of University College London, and colleagues, reported online in the Journal of Epidemiology and Community Health.

Spaghetti squash, an under-utilized vegetable

The population under study was English. In addition to lower risk of death, the heavy fruit and vegetable consumers had lower rates of cancer and cardiovascular disease. Click for the actual research report.

If seven servings a day seems like a lot, note that a typical serving is only half a cup. You’ll get those with the Low-Carb Mediterranean Diet.

For hypertension, coronary heart disease, and stroke, there is convincing evidence that increasing the consumption of vegetables and fruit reduces the risk of disease. There is probable evidence that the risk of cancer in general is inversely associated with the consumption of vegetables and fruit. In addition, there is possible evidence that an increased consumption of vegetables and fruit may prevent body weight gain. As overweight is the most important risk factor for type 2 diabetes mellitus, an increased consumption of vegetables and fruit therefore might indirectly reduces the incidence of type 2 diabetes mellitus. Independent of overweight, there is probable evidence that there is no influence of increased consumption on the risk of type 2 diabetes mellitus. There is possible evidence that increasing the consumption of vegetables and fruit lowers the risk of certain eye diseases, dementia and the risk of osteoporosis. Likewise, current data on asthma, chronic obstructive pulmonary disease, and rheumatoid arthritis indicate that an increase in vegetable and fruit consumption may contribute to the prevention of these diseases. For inflammatory bowel disease, glaucoma, and diabetic retinopathy, there was insufficient evidence regarding an association with the consumption of vegetables and fruit.

It bothers me that vegetables and fruits are lumped together: they’re not the same.

Heart attacks and cancer are the first and second leading causes of death in the developed world.

So just why, again, are we supposed to be eating our fruits and vegetables?

Here’s most of the abstract written by the epidemiologists:

This Review summarizes the evidence for a relationship between fruit and vegetable consumption and the occurrence of coronary heart disease…Most of the evidence supporting a cardioprotective effect comes from observational epidemiological studies; these studies have reported either weak or nonsignificant associations. Controlled nutritional prevention trials are scarce and the existing data do not show any clear protective effects of fruit and vegetables on coronary heart disease. Under rigorously controlled experimental conditions, fruit and vegetable consumption is associated with a decrease in blood pressure, which is an important cardiovascular risk factor. However, the effects of fruit and vegetable consumption on plasma lipid levels, diabetes, and body weight have not yet been thoroughly explored. Finally, the hypothesis that nutrients in fruit and vegetables have a protective role in reducing the formation of atherosclerotic plaques and preventing complications of atherosclerosis has not been tested in prevention trials. Evidence that fruit and vegetable consumption reduces the risk of cardiovascular disease remains scarce thus far.

What do they mean by controlled prevention trials? Here’s an example. Find 20,000 people with similar characteristics. Randomly assign half of them to eat significantly more fruits and vegetables, and make sure they do it. The other half eats their usual way, and make sure they do it. Analyze the entire group’s health and food consumption after 10 years and see which half has more or less heart disease.

Such a study is very difficult and costly. Even if the fruit and veggie group had less heart disease, someone would argue that the heart benefit was gained because of what they cut out of their eating to make way for the fruits and veggies! “They quit eating Cheetos; that’s why they had fewer heart attacks.”

Bottom Line

Fruits and vegetables don’t prevent heart disease, according to these researchers.

Fruits and vegetables are components of overall healthy diet patterns such as the Mediterranean diet, the DASH diet, and the “prudent diet.” Is it possible they reduce the risk of stroke, the second leading cause of death? I’ll leave that for another day.

I’m starting to think if I read enough nutritional literature, I won’t know anything with certainty.

Researchers looked at data from over 450,000 participants (men and women over 50) in the National Institutes of Health—AARP Diet and Health Study. Diet data was collected by self-administered questionnaire. State-level cancer registries identified the cancers that developed during the average follow-up of seven years.

Their conclusions and selected comments:

Intake of fruit and vegetables was generally unrelated to total cancer incidence in this cohort.

However, on the basis of animal studies, human case control and cohort studies, and randomized controlled trials, there is likely no harm associated with the consumption of fruit and vegetables and their consumption may prevent cardiovascular disease.

Indeed, analyses in this cohort and in others that have investigated dietary patterns rich in fruit and vegetables have found reduced risks of colorectal cancer [three references cited] and mortality, including death from cardiovascular disease and all cancers [one reference was cited supporting reduced deaths from CVD and all cancers—a Mediterranean diet study].

As in all good science reports, the researchers compare and contrast their findings with similar published research. They note that theirs is one of only four large cohort studies that have examined this issue. Two of the other three (see references below) also found no association between total cancers and fruit and vegetable consumption. The one that did find a beneficial linkage was the smallest of the four, so not as compelling.

Before this research was published, some experts suggested that adequate fruit and vegetable intake could prevent between 5 and 12% of cancers.

Eat your fruits and vegetables because they taste good, provide myriad nutrients, and may have some other healthful properties. But not to lower overall cancer risk.

Harvard’s Dr. Frank Hu in 2007 called for a paradigm shift in dietary prevention of heart disease, de-emphasizing the original diet-heart hypothesis and noting instead that “. . . reducing dietary GL [glycemic load] should be made a top public health priority.” Jim Mann at the University of Otago (Dunedin, New Zealand) authored a 2007 review of carbohydrates and effects on heart disease and diabetes. Here are highlights from the article summary in the European Journal of Clinical Nutrition:

The nature of carbohydrate is of considerable importance when recommending diets intended to reduce the risk of type II diabetes and cardiovascular disease and in the treatment of patients who already have established diseases. Intact fruits, vegetables, legumes and whole grains are the most appropriate sources of carbohydrate. Most are rich in [fiber] and other potentially cardioprotective components. Many of these foods, especially those that are high in dietary fibre, will reduce total and low-density lipoprotein cholesterol and help to improve glycaemic control in those with diabetes.

Frequent consumption of low glycaemic index foods has been reported to confer similar benefits, but it is not clear whether such benefits are independent of the dietary fibre content of these foods or the fact that low glycaemic index foods tend to have intact plant cell walls.

A wide range of carbohydrate intake is acceptable, provided the nature of carbohydrate is appropriate. Failure to emphasize the need for carbohydrate to be derived principally from whole grain cereals, fruits, vegetables and legumes may result in increased lipoprotein-mediated risk of cardiovascular disease, especially in overweight and obese individuals who are insulin resistant.

Why does this matter to me and readers of this blog? Dietary carbohydrates are a major determinant of blood sugar levels, tending to elevate them. Chronically high blood sugar levels are associated with increased complication rates from diabetes. People with diabetes are prone to develop heart disease, namely coronary artery disease, which causes heart attacks, weakness of the heart muscle, and premature death.